Answer:
The car stops in 7.78s and does not spare the child.
Explanation:
In order to know if the car stops before the distance to the child, you take into account the following equation:
(1)
vo: initial speed of the car = 45km/h
a: deceleration of the car = 2 m/s^2
t: time
xo: initial distance to the child = 25m
x: final distance to the child = 0m
It is necessary that the solution of the equation (1) for time t are real.
You first convert the initial speed to m/s, then replace the values of the parameters and solve the quadratic polynomial for t:


You take the first value t1 because it has physical meaning.
The solution for t is real, then, the car stops in 7.78s and does not spare the child.
Answer:
F₁ = 4 F₀
Explanation:
The force applied on the string by the ball attached to it, while in circular motion will be equal to the centripetal force. Therefore, at time t₀, the force on ball F₀ is given as:
F₀ = mv₀²/r --------------- equation (1)
where,
F₀ = Force on string at t₀
m = mass of ball
v₀ = speed of ball at t₀
r = radius of circular path
Now, at time t₁:
v₁ = 2v₀
F₁ = mv₁²/r
F₁ = m(2v₀)²/r
F₁ = 4 mv₀²/r
using equation (1):
<u>F₁ = 4 F₀</u>
Answer:
The electric field is 
Explanation:
Given that,
Radius = 2.00 cm
Number of turns per unit length 
Current 
We need to calculate the induced emf

Where, n = number of turns per unit length
A = area of cross section
=rate of current
Formula of electric field is defined as,

Where, r = radius
Put the value of emf in equation (I)
....(II)
We need to calculate the rate of current
....(III)
On differentiating equation (III)

Now, put the value of rate of current in equation (II)


Hence, The electric field is 
Answer:
1 question is- I believe 4. Melting Question 2 is Density
Explanation:
THOUGHT ABOUT IT!!!